From 081c96621da658760b4a67c07530805f770fa22c Mon Sep 17 00:00:00 2001
From: "Vladimir N. Makarov" <vmakarov@redhat.com>
Date: Wed, 27 Jan 2021 14:53:28 -0500
Subject: [PATCH] [PR97684] IRA: Recalculate pseudo classes if we added new
 pseduos since last calculation before updating equiv regs

update_equiv_regs can use reg classes of pseudos and they are set up in
register pressure sensitive scheduling and loop invariant motion and in
live range shrinking.  This info can become obsolete if we add new pseudos
since the last set up.  Recalculate it again if the new pseudos were
added.

gcc/ChangeLog:

	PR rtl-optimization/97684
	* ira.c (ira): Call ira_set_pseudo_classes before
	update_equiv_regs when it is necessary.

gcc/testsuite/ChangeLog:

	PR rtl-optimization/97684
	* gcc.target/i386/pr97684.c: New.
---
 gcc/ira.c                               | 12 +++++++++---
 gcc/testsuite/gcc.target/i386/pr97684.c | 24 ++++++++++++++++++++++++
 2 files changed, 33 insertions(+), 3 deletions(-)
 create mode 100644 gcc/testsuite/gcc.target/i386/pr97684.c

diff --git a/gcc/ira.c b/gcc/ira.c
index f0bdbc8cf56..c32ecf814fd 100644
--- a/gcc/ira.c
+++ b/gcc/ira.c
@@ -5566,6 +5566,15 @@ ira (FILE *f)
   if (warn_clobbered)
     generate_setjmp_warnings ();
 
+  /* update_equiv_regs can use reg classes of pseudos and they are set up in
+     register pressure sensitive scheduling and loop invariant motion and in
+     live range shrinking.  This info can become obsolete if we add new pseudos
+     since the last set up.  Recalculate it again if the new pseudos were
+     added.  */
+  if (resize_reg_info () && (flag_sched_pressure || flag_live_range_shrinkage
+			     || flag_ira_loop_pressure))
+    ira_set_pseudo_classes (true, ira_dump_file);
+
   init_alias_analysis ();
   loop_optimizer_init (AVOID_CFG_MODIFICATIONS);
   reg_equiv = XCNEWVEC (struct equivalence, max_reg_num ());
@@ -5610,9 +5619,6 @@ ira (FILE *f)
       regstat_recompute_for_max_regno ();
     }
 
-  if (resize_reg_info () && flag_ira_loop_pressure)
-    ira_set_pseudo_classes (true, ira_dump_file);
-
   setup_reg_equiv ();
   grow_reg_equivs ();
   setup_reg_equiv_init ();
diff --git a/gcc/testsuite/gcc.target/i386/pr97684.c b/gcc/testsuite/gcc.target/i386/pr97684.c
new file mode 100644
index 00000000000..983bf535ad8
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr97684.c
@@ -0,0 +1,24 @@
+/* PR rtl-optimization/97684 */
+/* { dg-do compile } */
+/* { dg-options "-O1 -flive-range-shrinkage -fschedule-insns -fselective-scheduling -funroll-all-loops -fno-web" } */
+
+void
+c5 (double);
+
+void
+g4 (int *n4)
+{
+  double lp = 0.0;
+  int fn;
+
+  for (fn = 0; fn < 18; ++fn)
+    {
+      int as;
+
+      as = __builtin_abs (n4[fn]);
+      if (as > lp)
+        lp = as;
+    }
+
+  c5 (lp);
+}
-- 
2.30.2